GetUpperBound(0) returns the upper bound for the indexes of the first dimension of the Array, and GetUpperBound(Rank - 1) returns the upper bound of the last dimension of the Array.

The GetUpperBound method is not affected by the number of elements in the array if the array is empty. The value of the Length property can never be greater than the number of elements allowed, as determined by the upper bound. For example, an array with an upper bound of 10 elements can never have a length greater than 9 (0 represents the first element).